He discounts that the writer could have written the letter with their off-hand, by saying that doing so won't change the size of your hand-writing over the course of a month, or how you draw the letters. But I think that's clearly false. Writing with your off-hand if you've never done it before does make things a lot looser, and is harder. The fact that every action is mirror-reversed can make you draw things differently, and you'd definitely improve with your off-hand fairly rapidly: you lack control which could explain the R's change from full loops to controlled arcs over time, the size and spacing, lining up of text gets better. That's all what I'd expect if someone was practicing off-hand writing over a few weeks. The lack of punctuation could be because the person was straining to write properly with the off-hand so forgot about punctuation at the start.
And it's not a "wake up sheeple" video, because the guy he pins it on is in fact the guy the official Bush administration investigation pinned it on. But in the vid, he claims the perp got another person's kid that his wife was babysitting to write it, and that the kids handwriting improved that much over the course of three weeks. Was the kid being given constant "DEATH TO ISRAEL" writing drills for three whole weeks without the guys wife noticing?
Also the mispelling of "Penicillin" as "childish" "penacilin" just seems like it makes the wrong errors. It's too correct in some ways, too wrong in other ways for a kid of 6-7 who wouldn't have learned that in school, and if the kid is copying it, then they wouldn't just randomly throw and "A" into a word which only has a lot if "I"s. And of course, perfectly spelling Israel.